The invention is based on a fuel injection pump for internal combustion engines as set forth hereinafter. German patent disclosure DE-OS 31 42 715 discloses a fuel injection pump of this kind, in which a feed pump driven synchronously with the engine speed fills the suction chamber of a fuel injection pump with fuel, which is embodied as a distributor pump. This fuel in the suction chamber is under continuous pilot pressure, which depends upon the speed of the engine, and is employed there for adjusting the onset of injection of the fuel injection pump by being carried to an injection onset adjusting device. In the known fuel injection pump, this injection onset adjusting device is constituted by an injection adjusting piston which can move axially in a cylinder lining, one face end of the piston is acted upon by the pressure in the fuel suction chamber in such a way that upon increasing suction chamber pressure, the injection onset adjusting piston is axially moved against the force of a restoring spring.
This axial adjusting movement of the injection onset adjusting piston, which movement depends upon the suction chamber pressure or upon the speed of the engine, is converted into a rotary motion of a cam ring via a bolt, which protrudes radially from the injection onset adjusting piston and into a recess of the cam ring of the cam drive, which drives the fuel injection pump; the injection onset adjusting piston acts upon the cam ring so that upon increasing suction chamber pressure, i.e. upon increasing speed of the engine, it is rotated in the direction of an earlier supply onset.
However, the injection onset adjusting device of the known fuel injection pump has the disadvantage that the additional injection adjusting piston disposed on and guided in the pump housing requires a lot of space, which in modern fuel injection systems has a negative impact on the overall installation space required. Furthermore, due to the great number of elements required, the injection adjusting device of the known pump makes for cost-intensive production. A further disadvantage of the known injection adjusting device, moreover, is the limited adjusting range of approximately 15.degree.-17.degree. of the cam ring rotational angle, which is due not only to the window-like access to the cam ring, but also to the one-sided action of force upon the cam ring, which can lead to one-sided surface pressures along with the attendant disadvantages, so that the adjusting device of the known fuel injection pump no longer sufficiently fulfills the current requirements.